Grubby grout makes a whole bathroom look dirty even when the tiles are spotless. We clean bathrooms for a living, so we get through a lot of grout products, and the right one turns an hour of scrubbing into a spray and a wipe. These are the five we rate for 2026, chosen from what is actually on UK shelves now: bleach sprays for black mould, a colour-safe spray that lifts grime without bleaching, and a white pen for grout that is past cleaning.
One thing to sort out before you buy, because it is the mistake we see most. A grout cleaner cleans, a grout pen recolours. If your grout is dirty or mouldy, a spray will bring it back. If it is permanently grey, cracked or stained right through, no cleaner will fix it and a white pen is the cheap answer. We have flagged which job each product is for, kept an honest safety note on bleach and ventilation near the end, and added a short note on how we do grout by hand on a job. If a tiled room needs more than a spray, our deep cleaning team covers it, and an end of tenancy clean includes the bathroom grout as standard. Working through the rest of the bathroom? See our tile cleaners and handheld steam cleaner picks, since steam lifts grout grime with no chemicals at all.
Best grout cleaners: quick comparison
| Product | Form | Size | Action | Targets | Approx UK price |
|---|---|---|---|---|---|
| HG Grout Cleaner | Ready-to-use spray | 500ml | Non-bleach, buffered | Dirt and discolouring, colour-safe | About £3.50–£4.50 |
| Astonish Mould & Mildew Blaster | Trigger spray | 750ml | Chlorine bleach (extra strength) | Black mould, mildew stains | About £3–£3.50 |
| Dettol Mould & Mildew Remover | Trigger spray | 750ml | Bleach, kills 99.9% bacteria | Mould plus germs, grout | About £3.50–£4 |
| Cif Perfect Finish Mould Stain Remover | Trigger spray | 435ml | Bleach (under 5%) | Mould, mildew, tea and wine stains | About £2.49–£2.75 |
| UniBond Anti-Mould Grout Reviver Pen | Pen (white coating) | 7ml | Recolours, anti-mould coating | Faded, discoloured grout joints | About £5.49–£7 |
HG Grout Cleaner
A non-bleach spray that lifts grime and brings grout back to its real colour.
| Form | Ready-to-use spray |
|---|---|
| Size | 500ml trigger bottle (concentrate also sold) |
| Action | Non-bleach, buffered cleaner, colour-safe |
| Targets | Dirt and discolouring in wall and floor tile grout |
| Applicator | Spray, then scrub with a brush |
| Price | About £3.50–£4.50 |
Reasons to buy
- Non-bleach and colour-safe, so it works on grey, beige and coloured grout, where bleach would blotch
- Buffered formula keeps its cleaning strength while it soaks and you scrub, which most sprays do not
- Restores grout to its original colour rather than bleaching it pale
- Made for both wall and floor grout, and widely stocked in the UK
Reasons to avoid
- You do have to scrub, this is a cleaner not a no-effort spray
- It cleans grime, not black mould, for that you want a bleach spray below
- Dearer than a basic supermarket bleach spray
This is the one we point most people to first, because it cleans the widest range of grout safely. You spray it on liberally, leave it a couple of minutes, then scrub with a brush and rinse with clean water. HG’s trick is the buffered formula, which holds its strength while it sits and while you work, so it keeps lifting dirt instead of going flat the moment it touches the surface. On normal grimy, greyed grout it does a genuinely good job.
Because it is non-bleach, it is safe on coloured and dark grout that a bleach spray would blotch, and it brings the real colour back rather than just hiding stains. The catch is black mould: HG themselves say black grout usually means mould, which is a job for a mould spray, not this. So buy it as your everyday grout cleaner and keep a bleach spray for the mouldy corners.
Where to buy
Sold at Wilko, B&M, Lakeland, Robert Dyas and Amazon, with a concentrate version too. Affiliate links coming soon — price last checked May 2026.
Astonish Specialist Extra Strength Mould & Mildew Stain Blaster
A strong bleach spray that clears black mould from grout with no scrubbing.
| Form | Trigger spray |
|---|---|
| Size | 750ml |
| Action | Chlorine bleach, 25% more than the standard formula |
| Targets | Black mould and mildew on grout, tiles, sealant, uPVC |
| Applicator | Spray, leave a few minutes, wipe (no scrub) |
| Price | About £3–£3.50 |
Reasons to buy
- Clears tough mould and mildew stains in minutes, no scrubbing needed
- Extra-strength version packs 25% more chlorine bleach than the standard Astonish formula
- Big 750ml trigger covers walls, grout, silicone sealant, shower curtains and uPVC frames
- Vegan, cruelty-free and made in Britain, in a recyclable bottle
Reasons to avoid
- It is chlorine bleach, so gloves, ventilation and care are a must
- Will lighten coloured grout and must be kept off rubber, chrome, brass and aluminium
- Strong bleach smell while it works
When the grout has gone black, this is our pick. You spray it straight onto the mould, leave it a few minutes, up to ten for heavy patches, then wipe clean with a damp cloth. There is no scrubbing because the bleach does the lifting, and on the mildew stains that build up along shower grout and silicone it works fast. Astonish list grout, tiles, sealant and uPVC among what it suits, which covers most of a bathroom.
It is proper chlorine bleach, and the extra-strength version has more of it, so treat it with respect: gloves on, window open or extractor running, and keep it off coloured grout, rubber, chrome and metal trim, which Astonish flag as off-limits. Used sensibly on white grout and sealant it is one of the most effective mould sprays you can buy for the money. Never mix it with any other cleaner.
Where to buy
Sold at Poundstretcher, B&M, Home Bargains, Wilko and Amazon. Affiliate links coming soon — price last checked May 2026.
Dettol Mould & Mildew Remover Spray
Clears mould from grout and kills 99.9% of bacteria, good for family bathrooms.
| Form | Trigger spray |
|---|---|
| Size | 750ml |
| Action | Bleach (sodium hypochlorite), kills 99.9% of bacteria and viruses |
| Targets | Ingrained mould and mildew, discoloured grout |
| Applicator | Spray, leave up to 5 minutes, wipe (no scrub) |
| Price | About £3.50–£4 |
Reasons to buy
- Removes ingrained mould and mildew and cleans discoloured grout with no scrubbing
- Also kills 99.9% of bacteria and viruses, including coronavirus, so it sanitises as it cleans
- The pick for family bathrooms where you want germs dealt with as well as mould
- Trusted brand, in every supermarket, often around £3.50
Reasons to avoid
- Contains active bleach, so gloves and ventilation are needed, and Dettol say do not breathe the mist
- Will lighten coloured grout like any bleach spray
- Fresh scent is still a bleach smell underneath
If you want one spray that clears the mould and sanitises the surface, this is it. The active bleach breaks mould and mildew down so you wipe it away after about five minutes rather than scrubbing, and Dettol confirm it cleans discoloured grout, ceramic tiles, sealant, basins and acrylic baths. The bit that sets it apart is the germ-kill: it is tested to kill 99.9% of bacteria and viruses, which the cheaper mould sprays do not all claim.
That makes it our pick for bathrooms used by children or anyone more vulnerable to bugs, where mould and hygiene matter together. It is still a bleach, so the usual rules apply: wear gloves, open a window, and keep it off coloured grout and metal trim. For everyday germs across the rest of the home, our guide to the best all-purpose cleaners covers the antibacterial sprays too.
Where to buy
Sold at Tesco, Sainsbury’s, Morrisons, Ocado and Amazon. Affiliate links coming soon — price last checked May 2026.
Cif Perfect Finish Mould Stain Removal Spray
A cheap bleach spray that shifts mould stains off baths, showers and grout.
| Form | Trigger spray |
|---|---|
| Size | 435ml |
| Action | Chlorine bleach (under 5% sodium hypochlorite) |
| Targets | Mould, mildew, and tea and wine stains |
| Applicator | Spray from 10–15cm, leave 15–20 minutes, rinse |
| Price | About £2.49–£2.75 |
Reasons to buy
- The cheapest mould spray here, often around £2.49, and stocked everywhere
- Made for baths, toilets, showers, tiled walls and grout, so it covers the whole bathroom
- Tackles tea, wine and mildew marks as well as mould
- Works outdoors too, on garden furniture and play equipment
Reasons to avoid
- Wants a longer dwell, 15 to 20 minutes, and Cif say leave the room while it works
- Smaller 435ml bottle than the 750ml rivals, so less per pound than it first looks
- Not for anodised aluminium or lino, and coloured surfaces need a test first
For a cheap, do-the-job mould spray, Cif is the value pick. You spray it onto the stain from about 10 to 15cm, leave it to work for 15 to 20 minutes, then rinse or let it dry. It clears mould and mildew off grout, tiles, baths and showers, and it also lifts tea and wine stains, which is a handy extra. For a bottle that is usually under £2.50 it punches well above its price.
Two things to note. Cif are clear you should leave the room while it does its 15 to 20 minute soak, and that it is not for anodised aluminium or linoleum, with a patch test on anything coloured or unusual. The bottle is also smaller than the Astonish or Dettol at 435ml. None of that is a deal-breaker for the price, it just rewards reading the label. Same rules as any bleach: gloves, ventilation, never mix it.
Where to buy
Sold at Tesco, B&Q, The Range, Robert Dyas and Amazon. Affiliate links coming soon — price last checked May 2026.
UniBond Anti-Mould Grout Reviver Pen (Ice White)
Paints a fresh white layer over grout that is too far gone to clean.
| Form | Grout pen (white coating, not a cleaner) |
|---|---|
| Size | 7ml, Ice White; covers up to 60m of joints |
| Action | Recolours grout, anti-mould coating that repels, kills and prevents mould |
| Targets | Faded, discoloured, permanently stained grout joints |
| Applicator | Pen tip; clean and dry first, shake, paint on |
| Price | About £5.49–£7 |
Reasons to buy
- Fixes grout no cleaner can save: it paints a fresh ice-white layer over old, greyed or stained joints
- Pen tip gives precise lines, so the white goes on the grout and not the tiles
- Triple-protection anti-mould coating that repels, kills and prevents mould regrowth
- Dries in about 60 minutes and is waterproof after an hour, so the shower is usable the same day
Reasons to avoid
- It recolours, it does not clean, so you still clean and dry the grout first
- Ice White only, which can look slightly brighter than aged white grout next to it
- One 7ml pen is a small job, a whole bathroom may need two
This is the answer when cleaning has stopped working. Some grout is grey right through, cracked or stained so deep that no spray will shift it, and rather than re-grouting the wall you paint over it. You clean and dry the joints first, shake the pen, then run the tip along the grout lines to lay down a fresh ice-white layer. The pen shape keeps the white on the grout and off the tile face, which is the fiddly part done for you.
UniBond build in triple-protection mould resistance that repels, kills and prevents mould, it covers up to 60m of joints, and it dries in about an hour, after which it is waterproof and the shower is fine to use. It only comes in Ice White, so on older white grout the refreshed lines can look a touch brighter, and a 7ml pen suits a shower area rather than a whole tiled room. As a cheap fix for tired grout, though, it is the one we reach for.
Sold at B&M, Dunelm, Wilko, Robert Dyas, B&Q and Amazon. Affiliate links coming soon — price last checked May 2026.
Grout cleaner or grout pen: which do you need?
This is the first call to make, and it decides everything else. The two products do opposite jobs. A grout cleaner removes dirt and mould so the original grout shows through again. A grout pen, like the UniBond, leaves the dirt where it is and paints a new white layer over the top.
Use a cleaner first, always. Most grout that looks ruined is just dirty or mouldy, and a spray brings it back for a few pounds. Reach for a pen only when cleaning has genuinely failed, when the grout is greyed all the way through, cracked, or stained so deeply that bleach makes no difference. The pen is a cosmetic fix, not a clean, and it goes on over grout you have already cleaned and dried.
One more thing the pen is not: a repair. If the grout is crumbling or falling out, it needs re-grouting, not recolouring. A pen on failing grout just flakes off with it.
Bleach or non-bleach?
The other big choice is whether to bleach. It comes down to what is wrong with your grout and what colour it is.
Reach for bleach when there is black mould
Black or dark spots in grout and silicone are mould, and bleach is what clears them. The Astonish, Dettol and Cif sprays here all use chlorine bleach, and they lift mould stains with little or no scrubbing. On white grout and sealant they are the fast, effective answer.
Go non-bleach for coloured grout or general grime
If your grout is grey, beige, charcoal or any colour other than white, bleach will blotch and lighten it. A non-bleach cleaner like the HG lifts the grime without touching the colour, and it brings the real shade back. It is also the better pick if you simply dislike bleach fumes. The trade-off is that you scrub a bit, and it will not clear heavy black mould.
What about steam?
If you would rather use no chemicals at all, a handheld steam cleaner blasts grime out of grout with hot vapour and a detail brush. It is slower than a spray and will not whiten mould-stained grout the way bleach does, but it is chemical-free and good for upkeep. Our guide to the best handheld steam cleaners covers the ones worth buying.
Safety: bleach fumes and ventilation
Three of the five picks here are bleach, so be straight with yourself about what you are holding. Chlorine bleach burns skin and eyes and the fumes catch the back of your throat in a closed bathroom.
Wear gloves, every time, and open a window or run the extractor before you start. Never, ever mix a bleach spray with another cleaner, especially anything containing acid or ammonia such as a limescale remover or some all-purpose sprays, because the combination releases chlorine gas. Use one product, rinse, then the next if you must. And keep bleach off coloured grout, rubber seals, chrome, brass and aluminium trim, which it stains and corrodes.
If fumes are a problem, or there are young children, pets or anyone with a chest condition in the house, lean on the non-bleach HG or a steam cleaner instead. Whatever you use, our professional advice from the old version of this guide still stands: only clean grout when the area is dry and dust-free, so vacuum or wipe it down first.
How we clean grout by hand on a job
When we take on a neglected bathroom, we do not just spray and hope. First we get the grout properly dry and brush the loose dirt and dust out of the lines, because cleaner works far better on a dry, clean surface than a damp grimy one. Then we match the product to the problem: a non-bleach grout cleaner for general greying, a bleach spray only on the black mouldy runs along the silicone and the shower corners.
The tool that makes the difference is a stiff, narrow grout brush, not a sponge. You work along the line, not across it, and you give the cleaner its full dwell time before scrubbing, which is the step most people rush. For the worst mould we will lay bleach-soaked tissue or cotton wool right along the grout line so it stays wet against the stain instead of running off, then come back to it later.
The lesson for doing your own: dry it, brush it, give the product time, and use the right brush. The people who scrub for an hour are usually the ones who went in wet and impatient. If a whole tiled room is past the point you fancy tackling, that is what our regular domestic cleaning and deep cleaning teams are for.
How to choose a grout cleaner
Run through these before you buy, in order.
- What is wrong with the grout? Dirty and grey wants a cleaner like HG. Black and spotty is mould, so a bleach spray. Stained right through and beyond cleaning is a job for the white pen.
- What colour is the grout? White grout can take bleach. Coloured grout needs a non-bleach cleaner, or bleach will blotch it.
- How much grout? A 750ml trigger like the Astonish or Dettol covers a lot. The smaller Cif is fine for one shower, and a 7ml pen suits a shower area, not a whole room.
- Do fumes bother you? If so, go non-bleach or use steam, and keep the bathroom ventilated.
For most homes the honest answer is two products: a non-bleach cleaner like HG for everyday grout, and a cheap bleach spray for the mouldy corners. Add a white pen only if some of your grout is genuinely past saving.
How often should you clean grout?
A quick spray and wipe every couple of weeks keeps shower grout ahead of the mould, and a proper scrub every few months keeps the whole room looking clean. The real fix for recurring mould is drying the room, so wipe the tiles after a shower, leave the window open or run the extractor, because mould grows on damp grout, not clean dry grout.
If the bathroom has reached the stage where no amount of spraying helps, or you are moving out and want the deposit back, that is when to call us in. Our end of tenancy cleaning includes the bathroom grout, and a deep clean covers the lot across London, Liverpool and Manchester. For a price, ask us for a quote or call 0333 555 2076.
Frequently asked questions
What is the best grout cleaner in 2026?
For most people the HG Grout Cleaner is the best grout cleaner, because it is non-bleach and colour-safe, so it lifts grime and brings grout back to its original colour without bleaching it. For black mould, a bleach spray like the Astonish Mould & Mildew Blaster is more effective, and for grout that is too stained to clean, the UniBond Grout Reviver Pen paints a fresh white layer over it.
What is the difference between a grout cleaner and a grout pen?
A grout cleaner removes dirt and mould so the original grout shows through again, while a grout pen leaves the dirt and paints a new white layer over the top. Use a cleaner first, because most dirty grout cleans up. Only use a pen, like the UniBond, when the grout is greyed right through or stained so deeply that cleaning no longer works, and always clean and dry it first.
How do you clean black mould out of grout?
Use a bleach-based mould spray. Spray it directly onto the black grout, leave it for the time on the label, around five minutes for Dettol or up to 15 to 20 for Cif, then wipe or rinse, and the stain lifts with little scrubbing. Wear gloves, open a window, and never mix the spray with another cleaner. For stubborn runs, hold the bleach against the line with soaked tissue so it stays wet.
Can you use bleach on coloured grout?
No, bleach will blotch and lighten coloured grout, so keep it for white grout only. For grey, beige, charcoal or any coloured grout, use a non-bleach cleaner like the HG Grout Cleaner, which lifts the dirt without changing the colour. If you are not sure how a product will react, test it on a hidden patch of grout first and wait a few minutes.
Do grout pens actually work?
Yes, for what they are, which is recolouring rather than cleaning. A pen like the UniBond paints a fresh ice-white waterproof layer over old grout and, applied to clean dry joints, it looks neat and lasts. It will not clean dirt away or repair crumbling grout, so it is a cosmetic fix for grout that is stained beyond cleaning, not a substitute for a cleaner or for re-grouting.
Is it safe to use grout cleaner without gloves?
Not the bleach ones. The Astonish, Dettol and Cif sprays all contain chlorine bleach, which irritates skin and eyes, so gloves and ventilation are needed and you should not breathe the mist. A non-bleach cleaner like the HG is gentler, but gloves are still sensible. If you want to avoid harsh chemistry around children or pets, a steam cleaner uses only hot water.
How do I stop mould coming back in grout?
Keep the grout dry, because mould grows on damp grout, not clean dry grout. Wipe the tiles down after a shower, leave the window open or run the extractor fan, and deal with any leaks. A spray with an anti-mould action, or the UniBond pen’s anti-mould coating, slows regrowth, but ventilation is what actually keeps it away. A quick weekly wipe stops it getting a hold in the first place.
Can you clean grout with a steam cleaner?
Yes, a handheld steam cleaner with a detail brush blasts grime out of grout using only hot vapour, with no chemicals. It is good for upkeep and for anyone avoiding bleach, though it is slower than a spray and will not whiten mould-stained grout the way bleach does. For badly stained grout, clean it with a spray first, then use steam to keep it fresh. See our best handheld steam cleaners guide for the models worth buying.
Last updated 29 May 2026. Written by the team at Monster Cleaning, professional cleaners working in UK homes since 2014. Prices, pack sizes and formulations were checked against UK retailers and manufacturer listings at the time of writing and do change.